Shoes with rubber soles might melt when exposed to high temperatures. The most effective way to repair a melted rubber sole is to replace it. If you are constantly working with equipment or materials that might melt rubber, replacing the rubber sole with a leather one might be your best option. However, if the means in which the sole of the shoe became melted is not something that is frequently encountered, a new rubber sole would work just fine. A new shoe sole can easily be applied — and it's a cheaper alternative to buying a new pair of shoes.
Take your shoes that you are repairing to a shoe supply store to find the proper sized sole.
Clean the shoe using soap, warm water and cleaning cloths. Dry the shoe completely once it's clean. Remove the insole.
Remove the melted sole of the shoe using the utility knife. Cut it off where it is attached. Be very careful when using the utility knife, as it is very sharp. Try to cut in a motion going away from your body if possible.
Rough up the area of the shoe where the sole was attached using the file. This will help create a surface for the new sole to securely attach.
Apply the shoe repair cement to the entire bottom of the shoe and place the new sole on. Place a small amount of the cement on the bottom of the insole and place it back into the shoe. Place the shoe into the vise. Hammer about five panel nails into the heel if you desire.
Walk around in the shoe once the adhesive has set to get a feel for the new sole. Make sure it is properly secured.